This invention relates to an improved door operating mechanism for a sliding door on the side wall of a gravity box.
Gravity box farm wagons are commonly used for transport of grain. Typically such boxes are rectangular in shape with a sloping bottom or floor. A passage or opening is usually provided on one side of the box so that grain within the box can follow the slope of the floor and flow through the side opening. Typically the box is also mounted on running gear so that it may be transported between the field and a storage facility or grain elevator. Also typically, a sliding door is provided for the grain discharge opening. Generally the door moves vertically along guide rails to open or close the opening.
Heretofore various mechanisms have been used to open and close the door. For example, the door may be attached to a pivoted lever arm to provide for raising or lowering of the door. Another mechanism for raising and lowering the door utilizes a rack and pinion arrangement wherein a rack is attached to the door and a pinion is attached to the side of the gravity box on an axle or shaft. Rotation of the pinion engages the rack and thereby lowers or raises the door.
While the aforesaid mechanisms are useful and efficient, an improved mechanism which is less expensive, easily installed, and may be incorporated with existing gravity boxes is desired.